1. Technical Field
The present invention relates to a liquid crystal display device.
2. Related Art
Some display devices use cathode-ray tubes (CRTs). Other display devices may be flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays (FED), and electro-luminescence displays (ELDs). Some of these flat panel displays may be driven by an active matrix driving method in which a plurality of pixels arranged in a matrix configuration are driven using a plurality of thin film transistors. Among these active matrix type flat panel displays, liquid crystal display (LCD) devices and electroluminescent display (ELD) devices may exhibits a higher resolution, and increased ability to display colors and moving images as compared to some of the other flat panel display devices.
An LCD device may include two substrates that are spaced apart and face each other with a layer of liquid crystal molecules interposed between the two substrates. The two substrates may include electrodes that face each other. A voltage applied between the electrodes may induce an electric field across the layer of liquid crystal molecules. The alignment of the liquid crystal molecules may be changed based on an intensity of the induced electric field, thereby changing the light transmissivity of the LCD device. Thus, the LCD device may display images by varying the intensity of the electric field across the layer of liquid crystal molecules.
FIG. 1 is a block diagram of a LCD device according to the related art. FIG. 2 is a circuit diagram of a liquid crystal panel of FIG. 1.
Referring to FIG. 1, the LCD device includes a liquid crystal panel 2 and a driving circuit 26. The driving circuit 26 may include gate and data drivers 20 and 18, a timing controller 12, a gamma reference voltage generator 16, a power supply 14 and an interface 10.
Referring to FIG. 2, the liquid crystal panel 2 includes a plurality of gate lines GL1 to GLn along a first direction and a plurality of data lines DL1 to DLm along a second direction.
The plurality of gate lines GL1 to GLn and the plurality of data lines DL1 to DLm cross each other to define a plurality of pixels. Each pixel includes a thin film transistor TFT and a liquid crystal capacitor LC. The liquid crystal capacitor LC includes a pixel electrode connected to the thin film transistor TFT, a common electrode, and a liquid crystal layer between the pixel and common electrodes.
Referring to FIG. 1, the interface 10 is supplied with data signals and control signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a data clock signal. The data signals and control signals are supplied from an external system, such as a computer system.
The timing controller 12 is supplied with the control signals from the interface 10 and generates control signals to control the gate and data drivers 20 and 18. The timing controller 12 processes data signals and supplies those to the data driver 18. The gate driver 20 is supplied with the control signals from the timing controller 12 to sequentially output gate voltages to the gate lines GL1 to GLn. The gate lines GL1 to GLn are sequentially enabled, and the thin film transistors TFT connected to the enabled gate line GL1, to GLn are turned on. The data driver 18 is supplied with the data signals and the control signals from the timing controller 12. The data driver 18 outputs data voltages to the data lines DL1 to DLm when the gate line GL1 to GLn is enabled.
The gamma reference voltage generator 16 generates gamma reference voltages which are supplied to the data driver 18. The power supply 14 supplies voltages that operate the components of the LCD device.
Even though not shown in the drawings, the LCD device includes a light source to supply light for the liquid crystal panel 2. The light source includes at least one lamp. The light source consumes much power. For example, regarding a small-sized LCD device of below 10 inches, power consumption of the light source is over 80% out of total power consumption of the LCD device.